This article explains how to clear the a commit error while configuring IPv6 address.

Commit failed with the following error message:

root@ex4600# commit
[edit interfaces irb unit 101 family inet6]
  'address 2001:288:3201:8:356:101:ffff:feff/96'
     Prefix length must be less than or equal to 64
error: configuration check-out failed

The specific configuration will trigger this commit error.

root@ex4600# set interfaces irb unit 101 family inet6 address 2001:288:3201:8:356:101:ffff:feff/96 eui-64

EUI-64 (Extended Unique Identifier)

• It is used to configure the IPv6 host addresses automatically
• IPv6 device will use the MAC address of its interface to generate a unique 64-bit interface ID
• For example:
  • Mac address of the device is 0121.1122.3EA8; calculate the corresponding EUI-64 address based on this MAC address
  • Split the MAC address in the middle
  • Insert FF:FE in the middle
  • Convert the first eight bits to binary and flip the 7 ^th bit  (1>>0 , 0 >>1)
    • Eg: 000000 0 1  >>> 000000 1 1
  • Convert these first eight bits back to hex
    

Use /64 prefix length while using EUI-64 and configure /96 prefix length without EUI-64.

Example: